The Pirates have placed opening-day starter Francisco Liriano on the 15-day disabled list due to a strained left oblique muscle, the club announced Wednesday. The lefty departed Tuesday night's start against the Cubs early due to the injury. As a corresponding move, the Pirates have recalled right-handed reliever Stolmy Pimentel from his rehab assignment. He had been on the DL since May 4 with a shoulder injury. No timetable was given as to a possible return for Liriano, but oblique injuries have been known to sideline guys for upwards of four to six weeks at times.